How to grow bricks from trillions of bacteria

This article was first published in the November 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

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Ginger Dosier, the North Carolina-based company's 37-year-old founder and CEO, hit on the bacterial production process while studying the construction of coral reefs. "I realised that, as with teeth, the building block is calcium carbonate," she explains. "This crystallises due to changes in the surrounding pH caused by microorganisms in the coral."

The bioMASON process begins with sand. It is placed into moulds and inoculated with Sporosarcina pasteuriibacteria, which are then fed with calcium ions suspended in water. "The ions are attracted to the bacterial cell walls, creating a calcium carbonate shell which causes particles to stick to each other," Dosier says.

A single bacterial brick takes two to five days to grow, compared with three to five days to make a kiln-fired version. "We can make bricks that glow in the dark, bricks that absorb pollution, bricks that change colour when wet," Dosier says.

A pilot plant in Durham, North Carolina, produces 500 bricks a week on average, with capacity for 1,500, and is currently working on an order to pave a courtyard from a Californian estate agent. Dosier's bacteria are also preparing to take on the cement manufacturers, an industry second only to fossil fuels for global carbon emissions. "The advantage of our process is that it doesn't require fuel," Dosier says. The next step is enabling customers to grow bricks on site. bioMASON has two licensees, and is in talks with five more. "We are looking at a powder or syrup that we can ship around the world," says Dosier. "You just add water."

This article was first published in the November 2015 issue of WIRED magazine